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Discussion Starter #1
Hey all, I have a bbc 468 did all myself I mean built all myself, and I go to put it in my 74 c20 truck and have had problems with the starter grinding and chewing up my flexplate I shimmed till it worked but you shouldnt have to shim that much. So bought a new starter hitachi high cranking starter and had more problems with that then the first so i just put in the stock one and lived with the shim for now.But every now and then it grinds until i tap it slow so it meshes back up. Come to find after doing research on the site and some serious brainstorming and found out my hitachi is 153 and 168 it fits both sizes and it bolts up straight across. My stock starter bolts up staggered so does the straight and staggered bolt pattern have to do with what size the flexplate is, and if so back to the original question which is better 153 or 168 and why do they use both sizes.I got a new flexplate thats the same size as what I have now which i think and pretty sure its 168. Since I have new plate and starter going to buy new bolts just to be safe so I have new evrything thats has to to with starter or starting. Thanks all.
 

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Some Punk Kid
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Just as a test for proper engagement use a paper clip end. You should be able to stick the end of the clip at the top of starter gear tooth when its in full mesh with the ring gear.
That should help you shim it.
 

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Unless BBCs are a lot different than other engines, the number of teeth depends on the diameter of the flexplate. A 153 tooth flexplate should be a little smaller in diameter than a 168 tooth. Not by much, but some. If the starter is good for both, that indicates (to me, I could be wrong) that the tooth pitch (number of teeth per inch) is the same for both flexplates. Has to be for the starter gear to properly engage the ring gear.

From what you've stated, I bet you have a 168 tooth flexplate installed when the block was machined for a 153 tooth -- assuming the starter bolts to the block and those are the only two choices of flexplates. The larger diameter flexplate would explain why you have to shim the starter so much. Hopefully some BBC boys will get on and confirm or refute my assumption on flexplate diameter.

I'm an AMC man, mainly sixes. There are two different tooth count flywheels for those, and they are different diameters. The same starter works with either, but you have to have the correct diameter (#of teeth) for the year engine because of starter mounting.
 

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Discussion Starter #5
Thanks guys got it all together and the 168th new plate and new starter grind without shims and when I shim it it gets worst what to do. I dont want to put stock starter back on I like this new hitachi mini-starter. Any help is much appreciated.
 

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If this engine hasn't been balanced you should stick to the 168t counterweighted flex plate. 400sbc's and 454s use an undercut harmonic ballancer and a flex plate with a counterweight. Anything else can cause major balance issues.
Genuine Gm starters come with different end housings for small and large flywheel starters. If your aftermarket starter is supposed to fit both it should have come with a range of mounting hardware and clear instructions-if not lose it. Many people think 153/168 is little different but it IS 10% gear reduction( like changing from a 3:1 to a 3.3:1 diff) so the change is noticable.
BTW, some L88 and Ls6 big blocks came with a small dia flywheel(153T) and a twin plate clutch - at least according to how to hot rod BBCs.
 

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Discussion Starter #7
Ian ur right about the nose cones and my hitachi starter has no nose cone so it fits both. Funny thing is got brand new 168 and new starter in and it doesnt mesh good unless i tap it first then start.I know something wrong so Im going to get the 153 to see if its better.
 

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will a 153 tooth spin the engine over faster since there are less teeth or is this a non issue. while the 168 will have more torque with the more teeth.???? just a thought. Ed ke6bnl
 

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I Think you'll find that Basically,....
Chevy has used 8 different Flywheels for All of their V-motors......

The 153t, 12" Flywheel is used with blocks that are Drilled,+ Tapped for the Straight Across Bolt Pattern Starters....

The 168t, 14" Flywheel is used with blocks that are D&Ted for the Staggered Bolt Pattern Starters.....

And, 'Course, Both these Flywheels came as Internal Balance,+ External Balance........

The Other 4 Flywheels used are the Same as the previous 4 with the exception of the fact that, Chevy changed the Crankshaft Bolt Pattern in 1987 when they went to the 1 piece Rear Main Oil Seal........

So,.... There are also Both 12",+ 14" Flywheels with Both Int.+ Ext. Balance, in 3",+ 3, 1/4" Crankshaft Bolt Patterns........

I Think that's 8........................ :)
 

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When the big center hole on the flexplate gets worn, the teeth will travel in a oval pattern (not in a circle) which cause the starter to get beat up when the teeth get too close to the starter gear.

I have also seen new flywheels not run true.

Pull the power to the coil, get under the car, and watch the plate spin when someone turns the key. You should be able to see if the plate is out of round.

I only use TCI plates after having problem with old stock and new B&M plates.

If it is working correctly, the stock starter and 168 tooth plate should start your BBC engine without any problems.
 
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